The 139 Marshallese living on Bikini Island will have to leave their home atoll within three months and not return for at least 30 years because of radiation remaining from a 1954 U.S. hydrogen bomb test, a House Appropriations subcommittee was told yesterday.

An earlier plan to move them from Bikini Island to Eneu, another island in the atoll, was dropped, the subcommittee was told, because Eneu's coconuts were showing radioactivity readings five to six times higher than government scientists had previously expected.

As a result, Interior Department officials said yesterday, they could not say where the Bikini residents would eventually end up.

The people now living on Bikini were the first ones to return after a 1969 determination by the Atomic Energy Commission that the atoll was safe from radiation contamination. From 1946 through 1968 it had been the site of 23 U.S. nuclear weapons tests.

Subcommittee Chairman Sidney Yates (D-Ill.) asked witness from the Departments of Interior and Energy. "Why were these people allowed to go back?"

"There was no hint in 1969 that there would be a problem with coconuts, vegetables and water," he was told by Ruth G. Van Cleve, director of Interior's Office of Territorial Activities.

Joe Deal, of Energy's safety branch, said, "There were no coconuts to test and no foodstuff growing . . . We used the best instruments available at that time."

Deal outlined to the subcommittee how last month's medical examination showed the Bikini residents had taken radioactive cesium into their bodies at levels up to twice the accepted U.S. standard for the general population.

Dr. Walter Wyzen, also of DOE, told the subcommittee that the 139 men, women and children who have been living on Bikini for the past several years and eating its radioactive coconuts and other foods would have to undergo medical examinations for the next year and perhaps the rest of their lives to keep track of the radioactive matter they have ingested.

It was the finding of high concentrations of radioactive cesium and strontium - above U.S. standards - in the bodies of the Bikini residents last month that convinced Interior officials the people had to be moved.

Van Cleve told the subcommittee that although "the tests (last month) do not reveal an immediate danger" the move from the atoll should be made within 90 days - the time needed to pick a temporary place to live and build plywood homes there with aluminum roofs.

Adrian P. Winkel, high commissioner of the U.S. Trust Territoy, told the subcommittee he would fly to Bikini next week and tell the residents "the need for the move and determine their preferences for a place to settle.

At that point, Rep. Frank Evans (D-Colo.) raised the question of what would be done if they did not want to leave Bikini.

"We have no choice but to require them to move," Winkel responded.

The high commissioner added, however, that it might be difficult to make the older people move because they still might prefer to remain.

Two aging Marshallese who own major pieces of land on Bikini Island are patriarchs of the two family groups that make up most of the people now living on the island.

Marshall Islanders who attended yesterday's subcommittee meeting were not sure Winkel could convince them to leave.

Illustrative of the problem was the exchange that took place when a question was asked why the people on Bikini kept eating coconuts after they had been warned they were dangerous and supplied with other food and water from outside the island.

Oscar DeBrum, the district representative of the Trust Territory government said, "Coconuts are treasured by the people. They would drink coconut milk even in the face of the warnings."

DeBrum then noted that when the medical team arrived last month on Bikini, the people offered them the radioactive coconuts as a sign of friendship.

"Either move the people or cut down the coconut trees," DeBrum suggested.

Representatives of the approximately 400 former Bikini people who now live on Kili Island told the subcommittee "we see ourselves as the victims of bureaucratic incompetence."

It was questioning by the Kili group about the safety of Bikini four years ago that first raised the possibility that dangerous radiation levels might still exist on the island.

At the time, U.S. officials were preparing to return the entire group to Bikini.

The Kill spokesman, Tomaki Juda, reminded the subcommittee that in 1946, a Navy officer told the Bikinians they had to leave their atoll so "it could be used for the good of mankind and to end all world wars."

The officer compared the Bikinians "to the children of Israel when the Lord saved from their enemy and led into the Promised Land."

"We are," Juda said, "sadly more akin to the Children of Israel when they left Egypt and wandered through the desert for 40 years. We left Bikini and have wandered through the ocean for 32 years and we will never return to our Promised Land."